Anal Fistulas and Fissures Treatment & Management

Anal fissure

Anal fissures can cause a vicious cycle in which the patient, in anticipation of pain associated with bowel movement, resists the urge to defecate, causing stools to become larger and harder, resulting in more pain with defecation. Treatment should be focused on breaking this cycle to allow healing. If the patient is having a great deal of pain, a topical anesthetic may be applied. Anal health care is particularly important. ^[17] Diet modification to soften stools is also indicated in patients with anal fissures. Patients should increase fruits, vegetables, and soluble and insoluble fibers in their diets and increase fluid intake to treat the acute phase and to prevent recurrence. Bulking agents such as psyllium may be prescribed. Approximately half of all anal fissures heal with nonoperative therapy within 2-4 weeks.

Use the WASH regimen in treatment of anal fissures, as follows:

• W arm water; sitz bath after bowel movement

• A nalgesics

• S tool softener

• H igh-fiber diet

Medications may also be prescribed for anal fissures, such as topical nitrates, calcium channel blockers, and onabotulinumtoxinA injections, and are considered first-line therapy. ^[18] These medications reduce anal sphincter tone or vasodilate, which, in turn, increases anodermal blood flow. When conservative treatment fails, surgical therapy may be an option to treat anal fissures.

A systematic review (inception to March 2017) and meta-analysis of 6 randomized controlled trials comprising 393 patients with chronic anal fissure found fewer side effects with botulinum toxin than with topical nitrates, but there were no significant differences in incomplete fissure healing or recurrence. ^[19]

Potential alternative strategies under investigation for treatment of anal fissures include using textile-based carrier systems loaded with microparticles containing nifedipine and lidocaine hydrochloride ^[20] as well as topical Myoxinol (hydrolyzed Hibiscus esculentus extract). ^[21]

Historically, surgical therapy was common for the treatment of anal fissures and is considered superior to nonoperative therapies. However, due to the risk of complications, including incontinence, surgical therapy is often reserved when conservative treatment fails to heal anal fissures.

2021 American College of Gastroenterology (ACG) recommendations ^[2]

In general, management of chronic anal fissures consists of stool softening and spasm reduction for improved regional perfusion.

ACG strongly recommends initial medical treatment of chronic anal fissure be local application of a calcium channel blocker (CCB).

ACG suggests a trial of botulinum toxin A injections in the setting of failed CCB therapy or as an alternative option to CCB. Another treatment option for chronic anal fissures is nitroglycerine.

Lateral internal sphincterotomy is strongly recommended as the surgical treatment of choice for chronic anal fissures refractory to nonsurgical measures.

Anal fistula

Treatment of anal fistulas depends on (1) the location of the fistula, (2) evidence of sepsis or a large abscess, or (3) worrisome findings on physical examination. If an abscess is present, drainage is indicated. Intravenous antibiotics, antipyretics, and analgesics are provided as needed. However, simple rectal abscesses do not typically need antibiotics. ^[22] If the patient also has sepsis, intravenous fluids or a pressor may be necessary. Depending on the presence of systemic symptoms and the condition of the patient, surgery may be necessary.

For anal fistulas, outpatient follow-up with a surgeon is indicated if consultation did not take place at the time of presentation. Surgical therapy is often indicated for healing of an anal fistula. The surgical approach is dependent on whether the fistula is simple or complex, as well as the risk of complications such as incontinence. A gastroenterologist should be consulted if inflammatory bowel disease is suspected. Asymptomatic anal fistulas from Crohn disease are not managed by surgery. However, if the patient is symptomatic, surgical management should be considered.

Antibiotics should be reserved for those with overlying cellulitis or those with sepsis. Otherwise, symptomatic treatment with analgesics should be considered.

In an open-label, single-arm clinical study by de la Portilla et al, local injections of expanded adipose-derived allogeneic mesenchymal stem cells proved beneficial for patients with perianal fistulas associated with Crohn disease. ^[23] The study involved 24 patients, with investigators finding that in 69.2% of cases, the number of draining fistulas was reduced, while in 56.3% of patients, the treated fissures closed completely, and in 30% of cases, all existing fistula tracts completely closed. ^[23]

A systematic review of the literature concluded that the advancement flap technique to treat anal fistulas in patients with Crohn disease is an adequate alternative management option. ^[24]

Guidelines

Consensus guidelines from a working group of the World Congress of Gastroenterology call for a multidisciplinary approach to the management of perianal fistulas associated with Crohn disease. The guidelines list surgical drainage of the abscesses as first-line treatment prior to starting immunosuppressive therapy. Definitive fistula repair with surgical treatment such as fistulotomy, ligation of the intersphincteric fistula tract (LIFT), or the use of mucosal advancement flaps, plugs, or fibrin glue should be considered only if there is no luminal inflammation. The guidelines also state that anti-tumor necrosis factor can provide first-line medical therapy, with an option being to combine this treatment with the use of antibiotics and/or thiopurines. ^[25]

Calcium channel blockers

Oral and topical calcium channel blockers (diltiazem and nifedipine) have been shown to be effective treatment options for anal fissures. Calcium channel blockers work by vasodilating blood vessels. In one review, calcium channel blockers were shown to be as effective as topical nitrates. Adverse effects such as headaches are common, especially with the use of oral calcium channel blockers. ^[26] Oral calcium channel blockers have been shown to yield decreased healing rates compared with topical calcium channel blockers, as well as higher rates of adverse effects. ^[27]

However, a prospective controlled trial that compared 2% diltiazem versus lateral internal sphincterotomy (LIS) for treatment of chronic anal fissures in 90 patients found LIS was more effective for not only complete healing at 6 weeks (96%) than diltiazem (71%) but also for pain relief. ^[28] The investigators suggested the use of topical diltiazem may be an initial conservative therapeutic option before consideration of surgical intervention.

Topical nitrates

Topical nitrates have been shown to be effective in the treatment of anal fissures. It is applied directly to the anus and vasodilates blood vessels. In a Cochrane review, topical nitrates were better than placebo in healing anal fissures (48.9% vs 35.5%). However, late recurrence was common (>50%) and headaches occurred frequently, causing cessation of therapy (up to 30%). ^[26]

In a study of 60 patients with chronic anal fissure, endoanal application of 375 g of 0.2% topical glyceryl trinitrate appeared to be associated with a slight reduction in headache intensity compared to perianal application, with a similar healing rate. ^[29]

Different dosing of topical nitrates has also been studied, from 0.05% to 0.4%, without a difference in healing rates. ^{[30, 31, 32]} Topical nitrates have also been compared with nitroglycerin patches applied to a remote area, with similar cure rates. ^[33]

One small randomized controlled trial between topical diltiazem gel (2%) or glyceryl trinitrate ointment (0.2%) showed a healing rate of 92% with diltiazem compared with 60% with glyceryl trinitrate (P< .001). ^[34] Adverse effects were more common with glyceryl trinitrate.

In a randomized clinical trial, Berkel et al investigated whether botulinum toxin A (Dysport) is more effective than isosorbide dinitrate ointment (ISDN) in the primary treatment of chronic anal fissure. Sixty patients were randomized to receive either ISDN 10 mg/ml (1%) (n = 33) or injection with 60 units of Dysport (n = 27). The primary end-point was the percentage of complete fissure healing after 8 weeks. After a median of 9 weeks, complete fissure healing was noted in 18 of 27 patients in the Dysport group, compared with 11 of 33 patients in the ISDN group (P = 0.010). Absolute improvement of pain scores after 9 weeks was similar between groups. Compared to patients treated with ISDN, patients treated with Dysport had fewer side effects. Of the patients with a healed fissure, 28% of the Dysport group and 50% of the ISDN group had a recurrence within 1 year. In the primary treatment of chronic anal fissure, Dysport is more effective than ISDN ointment and has fewer side effects. ^[35]

OnabotulinumtoxinA

OnabotulinumtoxinA is used typically to treat muscle hypertonia and cosmetic disorders. Typically, onabotulinumtoxinA is injected into the internal sphincter, reducing hypertonia. Various dosing schemes have been used, and it is typically injected on both sides of the anal fissure. Fissure healing appears to be equally effective with lower or higher doses of botulinum toxin, although lower doses reduced the risk of incontinence and recurrence over the long term. ^[36]

OnabotulinumtoxinA has been shown to be as effective as topical nitrates, but with fewer adverse effects, including headache, and can be an alternative to surgery. ^{[26, 37]} Botulism toxin has not been shown to be an effective treatment when other medical therapies have failed. ^[38]

Topical analgesics

Topical lidocaine can be used as an anesthetic to help relieve pain associated with anal fissures. Clove oil has also been studied and shows some promise in providing analgesia. ^[39]

Chronic anal fissures frequently require surgical treatment. ^[15] Surgical procedures may involve lateral internal sphincterotomy (LIS), anal dilation, or fissurectomy.

LIS is considered the treatment of choice for chronic anal fissure and can be performed either opened or closed. ^{[18, 40, 41]} It reduces the hypertonia of the internal anal sphincter, increases anodermal blood flow, decreases pain, and allows the fissure to heal. However, traditional LIS has been associated with relatively high rates of incontinence.

A systematic review and meta-analysis of the literature (inception to January 2017) that compared the efficacy of LIS with that of anal advancement flap (AAF) in 4 trials involving 300 patients found a significantly lower rate of anal incontinence than that of LIS, but wound complications and rate of unhealed fissures were comparable. ^[42]

Other surgical techniques have been described, including a more tailored approach, which showed lower rates of complications but higher rates of treatment failure. ^{[43, 44, 45]} LIS has been shown to have a higher rate of cure than anal dilation. Data for subcutaneous fissurectomy with anal advancement flap are limited, but promising. ^{[18, 46]}

Success has been reported for chronic anal fissure with associated anal fistula using a combined approach of fistulotomy and injection of botulinum A toxin. ^[47] A retrospective, observational study (2013-2016) of 20 patients with fissure-fistula treated with fistulotomy and botulinum toxin A found resolution of symptoms in all patients who attended follow-up appointments (mean, 10.5 weeks), with no reports of incontinence and no further operation required. ^[47]

For simple anal fistulas, fistulotomy with or without marsupialization is recommended. ^[22] In the presence of an abscess with anal fistula, incision and drainage along with fistulotomy may be considered. This is associated with decreased recurrence (relative risk, 0.17; 95% confidence interval, 0.09-0.32; P< .001) but increased risk of continence disturbance. ^[48] Fibrin glue has also been studied, with the advantage of less risk of incontinence. However, success rates have been reported lower than those for fistulotomy (41.7%).

For complex fistulas, debridement and fibrin glue or fistula plug may be used. Success rates for fibrin glue range from 10-67%. Although it has a relatively low success rate, recent guidelines suggest that fibrin glue may be used as first-line therapy. ^[22] Likewise, variable success has been reported with fistula plugs. One small trial described a success rate of 72.7% with the use of the Gore Bio-A fistula plug. ^[49] Endoanal advancement flaps also have variable success rates for the treatment of complex fistulas.

Ligation of intersphincteric fistula tract (LIFT) has also been described, with long-term success rates (>12 months) of 62%. ^[50] In this small study, fistula tract lengths greater than 3 cm were noted to have a higher rate of failure with LIFT (odds ratio, 0.55; 95% confidence interval, 0.34-0.88).

In a retrospective review of a prospectively collected database for evaluation of the healing rate after operations for anal fistulas in New England colorectal surgery practices, the healing rates of fistulotomy, advancement flap, and fistula plugs at 3 months were 94%, 60%, and 20%, respectively. ^[51] The healing rate of the ligation of intersphincteric fistula tract procedure at 3 months was 79%. Hospitals that performed more ligation of intersphincteric fistula tract procedures had higher healing rates at 3 months. ^[51]

In a retrospective study of 53 patients who underwent LIFT for anal fistula, of the 20 patients who had a failed LIFT at a median follow-up of 4 months, reoperation with placement of a seton followed by fistulotomy or rectal advancement flap appeared to resolve the fistula in 50% of these patients, with another nearly one third (31.7%) still undergoing therapy. ^[52] The majority of the recurrent fistulas was transsphincteric (75%) (25% intersphincteric).

Video-assisted anal fistula treatment (VAAFT) shows promise for safely and effectively managing perianal fistulas, regardless of comorbidity, underlying pathology, or type of fistula. ^{[53, 54]} Recurrence after VAAFT may be related to previous fistula surgery and the method of closure of the internal opening (eg, using staplers, after suturing, after advancement flap). ^[54]

Hong et al describe a new procedure, sphincter-preserving fistulectomy (SPF), as a safe and effective minimally invasive technique for the management of complex anal fistulas with a promising success rate. ^[55] They compared the outcomes of 35 patients who underwent a LIFT procedure with 41 patients who underwent SPF. Postoperative pain was comparable between the two groups and the SPF group had a lower morbidity rate and wound healing time. Outcome metrics were comparable, including Wexner scores, maximum resting anal canal pressure, maximum squeeze pressure, and fecal incontinence quality of life (FIQL) scores.{ref59) Additional studies are needed to determine long-term outcomes.

In some cases, staged surgery is needed to repair an anal fistula.